Inactivation of primary amines in beta-alanine detergent mixture compositions



United SW68 fi O INACTIVATION F PRIMARYAMINES IN p-ALANINE DETERGENT'MIXTURE COMPOSITIONS 1 1 David Aelony and Harold Wittcolf, Minneapolis,Minn.,

assignors to GeneralMills, Inc., a corporation of Delaware No Drawing.Application November 18, "1953,. Serial No. 393,015

5 Claims. (Cl. 260-482) The present invention relates to theinactivation of primary amines in [ii-alanine detergent mixturecompositions. The fi-alanine detergents contemplated by the presentinvention are those having the following formula: RNHCHzCHzCOOH in whichR is the long-chain aliphatic hydrocarbon group containing from 8 to 22carbon atoms. In place of the acid the salts and esters may be used.

These detergents may be made as disclosed in Isbell Patent 2,468,012.According to that patent primary fatty amines are condensed with methylacrylate to obtain the ester addition compound. This compound may thenbe hydrolized to the acid or converted to a salt such as the alkalimetal salts, ammonium salts, and other organic base salts.

Heretofore it has not been considered that any free primary amineremains in the reaction mixture. It has now been found however, thatunder some reaction conditions a small quantity of free primary aminemay remain in the reaction mixture and is difficult to remove. Thesefree primary amines may cause skin disorders and accordingly it isdesirable to obtain a detergent composition which is free from theprimary fatty amines. It has now been discovered that by reacting thedetergent composition with an aldehyde that the fatty primary amine maybe modified in such a way that the detergent composition does not causeskin disorders in case of persons sensitive to primary amines.

It is therefore an object of the present invention to provide a processof inactivating primary amine in alanine detergent mixture compositionsby means of an aldehyde. It is also an object of the present inventionto provide a novel fl-alanine detergent mixture composition in whichfree primary fatty amine has been inactivated by means of an aldehyde.

As disclosed in the Isbell patent a wide variety of primary fatty aminesmay be employed for the preparation of these detergents. These aminesmay contain from 8 to 22 carbon atoms and may be the mixed aminesobtained from the mixed fatty acids of an oil or from any selectedindividual acid or any selected group of acids. The amines may be thesaturated or unsaturated. These amines may be reacted with an acrylateester especially the lower aliphatic acrylate esters in which thealcohol group of the ester contains from 1 to 4 carbon atoms.

For the purpose of inactivating free primary amines it is preferred totreat the ester addition compound thus obtained rather than any of thehydrolysis products such as the acid or salts. However, it is alsopossible to inactivate the primary amine by treatment either of the acidobtained by hydrolysis of the ester or by treating the alkali metalsalts such as sodium and potassium salts of the acid.

The process of inactivating the primary amines involves the simpleaddition of an aldehyde to the detergent product. A wide variety ofaldehydes may be employed including both aromatic and aliphaticaldehydes. Benzaldehyde and salicylaldehyde has been found to beparticularly effective. Likewise the aliphatic aldehydes such asbutyraldehyde has been found to be very effective. Other aldehydes suchas formaldehyde and. glyoxal may also be used but are generally not asdesirable as some of the preferredaldehydes referred to above.

The aldehyde is merely added to the reaction mixture and no specialreaction conditions arerequired. The reaction proceedsat roomtemperature in a reasonable period of time. Thus since these detergentsare not ordinarily used immediately the aldehyde may simply be added tothe reaction mixture and reaction will have been completed by the timethat the detergent is used after having distributed through the normalchannels of commerce. If desired the reaction may be speeded up byemploying higher temperatures. Likewise it is not necessary to employsolvents, catalysts or other reaction aids, although, of course thesemay be used if desired. It is preferred to employ approximately anamount of the aldehyde equivalent to the free primary fatty amine.Generally this will result in a reduction of the free amine content toconsiderably less than 1% even when starting with a detergentcomposition containing as high as 10% of the free primary fatty amines.Naturally, if desired, excess aldehyde may be used.

Example 1 To prepare the p-alanine methyl ester, distilled amine derivedfrom coconut fatty acids was used. This product had an amine number of274.6. Amine number is defined as the mg. of KOH equivalent to the freeamine in 1 g. of product. It is determined by titrating a solution ofthe amine in ethyl alcohol toluene to a bromcresol green end point withaqueous hydrochloric acid. Also, it may be determined by titrating withperchloric acid in anhydrous acetic acid solution, as described byTerry, Eilar, and Moe in Analytical Chemistry (volume 24 for 1952).

The coco amine (306 g.) was heated to C. under a vacuum of 10 mm.Thereafter, it was cooled to 40 C. and methyl acrylate (142 g.) wasadded over a period of 8 minutes. The mixture was agitated at 40 C. for6 hours. Vacuum was applied and the mixture was heated to 100 C. at 40pto remove volatile material. The product weighed 438 g. It had an aminenumber of 188.6, a primary amine content of 8.2 and a secondary aminecontent of 83.9. To this ester (20 g.) was added salicylaldehyde (1.1g.) and the solution was allowed to stand for 24 hours. The primaryamine content at the end of this time had decreased to 0.5%.

Example 2 The above experiment was repeated save that 0.96 g. ofbenzaldehyde was used instead of salicylaldehyde. In this instance thefinal product had a primary amine content of 0.

Example 3 Amine number 170.9 Primary amine content 1.4 Secondary aminecontent 81.2 Tertiary amine content 13.7

This product (357 g.) was mixed with butyraldehyde (12 g.) and allowedto stand overnight at room temperature. 'The primary amine content ofthe treated material decreased from 1 .4 to- 0.09

We claim as our invention:

I. A process of inactivating free primary amines in a fl-alaninedetergent composition in which the 'fl-alanine contains an aliphatichydrocarbon substituent of from '8 to 22 carbon atoms on the aminonitrogen, which comprises reacting said 'fl-alanine detergentcomposition with an aldehyde which is reactive with primary amines toproduce products inert to human skin.

2. A process of inactivating free primary amines in a B-alaninedetergent composition in which the fl-alanine contains an aliphatichydrocarbon substituent of from 8 'to 22 carbon'atorns on the aminonitrogen which comprises reacting said p-alanine detergent composition15 with a quantity of an aldehyde substantially equivalent to thefreeuprimary amine content of the detergent composition, said aldehydebeing reactive with primary amines to produce products inert to humanskin.

3. Process according to claim 1 in which the aldehyde is benzaldehyde.

4. Process according to claim 1 in which the aldehyde issalicylaldehyde.

5. Process according to claim 1 in which the aldehyde 10 isbutyraldehyde.

References Cited in thefile of this patent UNITED STATES PATENTS2,468,012 Isbell Apr. 19; 1949

1. A PROCESS OF INACTIVATING FREE PRIMARY AMINES IN A B-ALANINEDETERGENT COMPOSITION IN WHICH THE B-ALANINE CONTAINS AN ALIPHATICHYDROCARBON SUBSTITUENT OF FROM 8 TO 22 CARBON ATOMS ON THE AMINONITROGEN, WHICH COMPRISES REACTING SAID B-ALANINE DETERGENT COMPOSITIONWITH AN ALDEHYDE WHICH IS REACTIVE WITH PRIMARY AMINES TO PRODUCEPRODUCTS INERT TO HUMAN SKIN.